- ID:
- ivo://CDS.VizieR/J/ApJ/815/58
- Title:
- Spectrophotometric time series obs. of twin SNIa
- Short Name:
- J/ApJ/815/58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We introduce a method for identifying "twin" Type Ia supernovae (SNeIa) and using them to improve distance measurements. This novel approach to SN Ia standardization is made possible by spectrophotometric time series observations from the Nearby Supernova Factory (SNfactory). We begin with a well-measured set of SNe, find pairs whose spectra match well across the entire optical window, and then test whether this leads to a smaller dispersion in their absolute brightnesses. This analysis is completed in a blinded fashion, ensuring that decisions made in implementing the method do not inadvertently bias the result. We find that pairs of SNe with more closely matched spectra indeed have reduced brightness dispersion. We are able to standardize this initial set of SNfactory SNe to 0.083+/-0.012mag, implying a dispersion of 0.072+/-0.010mag in the absence of peculiar velocities. We estimate that with larger numbers of comparison SNe, e.g., using the final SNfactory spectrophotometric data set as a reference, this method will be capable of standardizing high-redshift SNe to within 0.06-0.07mag. These results imply that at least 3/4 of the variance in Hubble residuals in current SN cosmology analyses is due to previously unaccounted-for astrophysical differences among the SNe.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/143/126
- Title:
- Spectroscopy of 462 nearby Type Ia supernovae
- Short Name:
- J/AJ/143/126
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 2603 spectra of 462 nearby Type Ia supernovae (SNe Ia), including 2065 previously unpublished spectra, obtained during 1993-2008 through the Center for Astrophysics Supernova Program. There are on average eight spectra for each of the 313 SNe Ia with at least two spectra. Most of the spectra were obtained with the FAST spectrograph at the Fred Lawrence Whipple Observatory 1.5m telescope and reduced in a consistent manner, making this data set well suited for studies of SN Ia spectroscopic diversity. Using additional data from the literature, we study the spectroscopic and photometric properties of SNe Ia as a function of spectroscopic class using the classification schemes of Branch et al. (2006PASP..118..560B) and Wang et al. (2009, Cat. J/ApJ/699/L139). The width-luminosity relation appears to be steeper for SNe Ia with broader lines, although the result is not statistically significant with the present sample. Based on the evolution of the characteristic SiII{lambda}6355 line, we propose improved methods for measuring velocity gradients, revealing a larger range than previously suspected, from ~0 to ~400km/s/day considering the instantaneous velocity decline rate at maximum light.
- ID:
- ivo://CDS.VizieR/J/ApJ/827/90
- Title:
- Spectroscopy of SNe Ib, IIb and Ic
- Short Name:
- J/ApJ/827/90
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the largest spectroscopic data set of stripped-envelope core-collapse supernovae (stripped SNe), we present a systematic investigation of spectral properties of Type IIb SNe (SNe IIb), Type Ib SNe (SNe Ib), and Type Ic SNe (SNe Ic). Prior studies have been based on individual objects or small samples. Here, we analyze 242 spectra of 14 SNe IIb, 262 spectra of 21 SNe Ib, and 207 spectra of 17 SNe Ic based on the stripped SN data set of Modjaz et al. (2016ApJ...832..108M) and other published spectra of individual SNe. Each SN in our sample has a secure spectroscopic ID, a date of V-band maximum light, and most have multiple spectra at different phases. We analyze these spectra as a function of subtype and phase in order to improve the SN identification scheme and constrain the progenitors of different kinds of stripped SNe. By comparing spectra of SNe IIb with those of SNe Ib, we find that the strength of H{alpha} can be used to quantitatively differentiate between these two subtypes at all epochs. Moreover, we find a continuum in observational properties between SNe IIb and Ib. We address the question of hidden He in SNe Ic by comparing our observations with predictions from various models that either include hidden He or in which He has been burnt. Our results favor the He-free progenitor models for SNe Ic. Finally, we construct continuum-divided average spectra as a function of subtype and phase to quantify the spectral diversity of the different types of stripped SNe.
- ID:
- ivo://CDS.VizieR/J/AJ/147/99
- Title:
- Spectroscopy of 73 stripped core-collapse supernovae
- Short Name:
- J/AJ/147/99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 645 optical spectra of 73 supernovae (SNe) of Types IIb, Ib, Ic, and broad-lined Ic. All of these types are attributed to the core collapse of massive stars, with varying degrees of intact H and He envelopes before explosion. The SNe in our sample have a mean redshift ${<}cz${>} = 4200 km/s. Most of these spectra were gathered at the Harvard-Smithsonian Center for Astrophysics (CfA) between 2004 and 2009. For 53 SNe, these are the first published spectra. The data coverage ranges from mere identification (1-3 spectra) for a few SNe to extensive series of observations (10-30 spectra) that trace the spectral evolution for others, with an average of 9 spectra per SN. For 44 SNe of the 73 SNe presented here, we have well-determined dates of maximum light to determine the phase of each spectrum. Our sample constitutes the most extensive spectral library of stripped-envelope SNe to date. We provide very early coverage (as early as 30 days before V-band max) for photospheric spectra, as well as late-time nebular coverage when the innermost regions of the SN are visible (as late as 2 yr after explosion, while for SN 1993J, we have data as late as 11.6 yr). This data set has homogeneous observations and reductions that allow us to study the spectroscopic diversity of these classes of stripped SNe and to compare these to SNe-gamma-ray bursts. We undertake these matters in follow-up papers.
- ID:
- ivo://CDS.VizieR/J/A+A/477/717
- Title:
- Spectroscopy of Type Ia supernovae
- Short Name:
- J/A+A/477/717
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a quantitative study of a new data set of high redshift Type Ia supernovae spectra, observed at the Gemini telescopes during the first 34 months of the Supernova Legacy Survey. During this time 123 supernovae candidates were observed, of which 87 have been identified as SNe Ia at a median redshift of z=0.720. Spectra from the entire second year of the survey and part of the third year (59 total SNe candidates with 46 confirmed SNe Ia) are published here for the first time. The spectroscopic measurements made on this data set are used determine if these distant SNe comprise a population similar to those observed locally. Rest-frame equivalent width and ejection velocity measurements are made on four spectroscopic features. Corresponding measurements are presented for a set of 167 spectra from 24 low-z SNe Ia from the literature.
- ID:
- ivo://CDS.VizieR/J/ApJ/867/108
- Title:
- Stellar masses and rest-frame u-g colors of SNIa
- Short Name:
- J/ApJ/867/108
- Date:
- 03 Dec 2021 00:48:50
- Publisher:
- CDS
- Description:
- Recent analyses suggest that distance residuals measured from Type Ia supernovae (SNe Ia) are correlated with local host galaxy properties within a few kiloparsecs of the SN explosion. However, the well-established correlation with global host galaxy properties is nearly as significant, with a shift of 0.06mag across a low to high mass boundary (the mass step). Here, with 273 SNe Ia at z<0.1, we investigate whether the stellar masses and rest-frame u-g colors of regions within 1.5kpc of the SN Ia explosion site are significantly better correlated with SN distance measurements than global properties or properties measured at random locations in SN hosts. At >~2{sigma} significance, local properties tend to correlate with distance residuals better than properties at random locations, though despite using the largest low-z sample to date, we cannot definitively prove that a local correlation is more significant than a random correlation. Our data hint that SNe observed by surveys that do not target a pre-selected set of galaxies may have a larger local mass step than SNe from surveys that do, an increase of 0.071+/-0.036mag (2.0{sigma}). We find a 3{sigma} local mass step after global mass correction, evidence that SNe Ia should be corrected for their local mass, but we note that this effect is insignificant in the targeted low-z sample. Only the local mass step remains significant at >2{sigma} after global mass correction, and we conservatively estimate a systematic shift in H0 measurements of -0.14km/s/Mpc with an additional uncertainty of 0.14km/s/Mpc, ~10% of the present uncertainty.
- ID:
- ivo://CDS.VizieR/II/201
- Title:
- Sternberg SN Catalogue, 1994Sep.
- Short Name:
- II/201
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a revised version of "Sternberg Astronomical Institute Supernova Catalogue" which includes data on 930 extragalactic supernovae (SNe) discovered up to September 1, 1994 and the main data on their parent galaxies. The description of previous version was presented by Tsvetkov and Bartunov (1993). The main improvements are the following: 1. The RC3 catalogue (de Vaucouleurs et al., 1991) was used instead of the RC2 as main source of data for parent galaxies. 2. For recent supernovae we included some magnitudes at maximum light from Hamuy et al. (1993) and compared our data with those of van den Bergh (1993). We also corrected some velocities of galaxies according to Huchra et al. (1994). 3. Some galaxy identifications from the MCG ( M ) were replaced by the ones from the PGC and the UGC. The identifications were adopted with this order of preference: NGC (IC) - UGC (ESO) - MCG - PGC - others 4. Photographic magnitudes from the PGC ( marked '*' ) and from IAU circulars ( marked 'C' ) were used when no other data were available. 5. Some errors were found in the previous version, and many new identifications for the galaxies previously listed as "ANON" were adopted. 6. We included several precise astrometric positions of SNe from Porter (1993).
- ID:
- ivo://CDS.VizieR/II/218
- Title:
- Sternberg Supernova Catalogue
- Short Name:
- II/218
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalogue presents the main data on 1362 extragalactic supernovae (SNe) discovered up to July 13, 1998 and on their parent galaxies. SNe are ordered by Right Ascension of their parent galaxies. Data for parent galaxies were compiled from the following catalogues: RC3 (de Vaucouleurs et al., 1991, Cat. <VII/155>); UGC (Nilson, 1973. Cat. <VII/26>); PGC (Paturel et al., 1989, Cat. <VII/119>); MCG (Vorontsov-Velyaminov et al., 1962-1968, Cat. <VII/62>, <VII/100>); ESO (Lauberts, 1982, Cat. <VII/34>); CfA (Huchra et al., 1994, see Cat <VII/193>), and from van den Bergh (1994, Cat. <J/ApJS/92/219>). Main source of morphological types, major diameters and axial ratios was the RC3; the data from other sources have been reduced to the system of RC3. Photographic magnitudes of galaxies were adopted from the UGC and the PGC together with individual data from the literature. The sources of recession velocities or cz values were the RC3, the CfA, the PGC and IAU Circulars. Position angles were taken from the RC3, UGC and the ESO catalogues, and inclination angles were mainly derived from data in RC3 according to Holmberg (1958MeLu2.136....1H). Some data for SNe and parent galaxies were adopted from GCVS (Samus et al., 1995, Cat. <II/205>)
- ID:
- ivo://CDS.VizieR/II/256
- Title:
- Sternberg Supernova Catalogue, 2004 version
- Short Name:
- II/256
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the Sternberg Astronomical Institute (SAI) catalog of supernovae. We show that the radial distributions of type-Ia, type-Ibc and type-II supernovae differ in the central parts of spiral galaxies and are similar in their outer regions, while the radial distribution of type-Ia supernovae in elliptical galaxies differs that in spiral and lenticular galaxies. We give a list a supernovae that are farthest from the galactic centers, estimate their relative expulsion rate, and discuss their possible origins.
- ID:
- ivo://CDS.VizieR/J/A+A/584/A62
- Title:
- SUDARE VST-OmegaCAM search supernova rates
- Short Name:
- J/A+A/584/A62
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the observing strategy, data reduction tools, and early results of a supernova (SN) search project, named SUDARE, conducted with the ESO VST telescope, which is aimed at measuring the rate of the different types of SNe in the redshift range 0.2<z<0.8. The search was performed in two of the best studied extragalactic fields, CDFS and COSMOS, for which a wealth of ancillary data are available in the literature or in public archives. We developed a pipeline for the data reduction and rapid identification of transients. As a result of the frequent monitoring of the two selected fields, we obtained light curve and colour information for the transients sources that were used to select and classify SNe by means of an especially developed tool. To accurately characterise the surveyed stellar population, we exploit public data and our own observations to measure the galaxy photometric redshifts and rest frame colours. We obtained a final sample of 117 SNe, most of which are SN Ia (57%) with the remaining ones being core collapse events, of which 44% are type II, 22% type IIn and 34% type Ib/c. To link the transients, we built a catalogue of ~1.3x10^5^ galaxies in the redshift range 0<z<=1, with a limiting magnitude K_AB_=23.5mag. We measured the SN rate per unit volume for SN Ia and core collapse SNe in different bins of redshifts. The values are consistent with other measurements from the literature. The dispersion of the rate measurements for SNe-Ia is comparable to the scatter of the theoretical tracks for single degenerate (SD) and double degenerate (DD) binary systems models, therefore it is not possible to disentangle among the two different progenitor scenarios. However, among the three tested models (SD and the two flavours of DD that either have a steep DDC or a wide DDW delay time distribution), the SD appears to give a better fit across the whole redshift range, whereas the DDC better matches the steep rise up to redshift ~1.2. The DDW instead appears to be less favoured. Unlike recent claims, the core collapse SN rate is fully consistent with the prediction that is based on recent estimates of star formation history and standard progenitor mass range.